This invention relates to a package for packaging a semiconductor device or chip and to a packaged semiconductor device in which the semiconductor device is packaged in the package.
Semiconductor devices are used in various electronic units or systems. Typically, a semiconductor device is connected to a connection object included in each of the electronic units. In connecting the semiconductor device to the connection object, use is made of a package for packaging the semiconductor device to protect it.
A conventional package is disclosed in Japanese Patent Prepublication (Kokai or Publication of Unexamined Patent Application) No. 206658/1992 by Hosono et al. As will later be described in detail in conjunction with the drawing, a conventional package comprises a metal plate, an insulator layer extending along the metal plate, and a plurality of conductive patterns each extending along the insulator layer and being connected to the semiconductor device that is packaged in the conventional package. The metal plate includes a central plate portion and a peripheral plate portion extending outwardly from the central plate portion. Together with the insulator layer and the conductive patterns, the peripheral plate portion is bent to have a flat surface extending substantially smooth and even. As a result, each of the conductive patterns has a flat portion which extends substantially flat on the flat surface of the peripheral plate portion.
The flat portion is connected to the connection object by soldering with the flat surface of the peripheral plate portion facing a principal surface of the connection object. During soldering, solder can extend along the principal surface of the connection object due to surface tension thereof form a short circuit between adjacent ones of the conductive patterns and to connect each of the conductive patterns with the peripheral plate portion of the metal plate. This is because the principal surface of the connection object is generally flat and parallel to the flat surface of the peripheral portion.